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TCRB (TRB) Breakapart

Catalogue Numbers
LPH 048-S (5 tests)
LPH 048 (10 tests)

Dysregulation of normal transcription is a feature of all types of acute leukaemia. In T-ALL, this is brought about by altered expression of normal transcription factor proteins, which is in contrast with AML and B-ALL, where chimaeric proteins are expressed and provide the drivers for the malignancy.

T-ALL composes around 12-15% of childhood ALL1. In about 30% of these cases, chromosomal rearrangements involving the T-cell receptor genes TRA@ (TCRA), TRB@ (TCRB), TRG@ (TCRG) and TRD@ (TCRD) have been described2. It has been suggested that a number of developmentally important transcription factor genes are dysregulated as a result of being brought into close proximity with the promoter and enhancer elements of one of these T-cell receptor genes3. These can be more clearly demonstrated by FISH than by using conventional cytogenetics4.

The TCRB T-cell Receptor gene on chromosome 7q34 is rearranged with the genes TLX1, HOX@, LYL1, TAL2, LCK and NOTCH1 following the t(7;10)(q34;q24); t(7;7)(p15;q34); t(7;19)(q34;p13); t(7;9)(q34;q32); t(1;7)(p34;q34) and t(7;9)(q34;q34) translocations respectively. The frequency of rearrangements varies between 7% (for the TLX1 rearrangement) to less than 1% (for TAL2, LYL1, LCK and NOTCH1)5.

In our hands, Cytocell FISH probes, have proven to be of the highest quality with bright, easy to interpret signals, thus providing confidence in our results. Cytocell’s customer support is outstanding, as their staff are extremely knowledgeable and truly care about their customers and their customers’ needs. Jennie Thurston, Director of Cytogenetics at Carolinas Pathology Group


1. Schneider NR et al., Blood 2000;96:2543-9

2. Secker-Walker LM, Chromosomes and Genes in Acute Lymphoblastic Leukaemia. New York: Chapman and Hall 1997

3. Raimondi SC. T-lineage acute lymphoblastic leukemia (T-ALL) Atlas Genet Cytogenet Oncol Haematol. May 2007

4. Gesk S et al., Leukemia 2003;17:738-45

5. Graux C et al., Leukemia 2006;20:1496-510

Microscope Images

TCRB (TRB) Breakapart magnified
Area of Interest*


This product is intended to be used on Carnoy’s solution (3:1 methanol/acetic acid) fixed haematological samples.

*Disease information supported by the literature and is not a reflection of the intended purpose of this product.